Hadith: Self-control is true strength

It is reported that the Prophet ﷺ said:

The strong man is not the one who overpowers an opponent. The strong man is the one who controls his own self in a moment of anger.

In Arabic:

لَيْسَ الشَّدِيدُ بِالصُّرَعَةِ إِنَّمَا الشَّدِيدُ الَّذِي يَمْلِكُ نَفْسَهُ عِنْدَ الْغَضَبِ

Notes

This hadith appears in Sahih Muslim, Sahih al-Bukhari, Malik's Muwatta' and other collections.